Adds a new MIME part to @multipart with the given headers and body. (The multipart will make its own copies of @headers and @body, so you should free your copies if you are not using them for anything else.)
the MIME part headers
the MIME part body
2.26
See Implementation
Adds a new MIME part to @multipart with the given headers and body. (The multipart will make its own copies of @headers and @body, so you should free your copies if you are not using them for anything else.)